[Federal Register Volume 64, Number 249 (Wednesday, December 29, 1999)]
[Proposed Rules]
[Pages 72963-72964]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-33734]


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 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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  Federal Register / Vol. 64, No. 249 / Wednesday, December 29, 1999 / 
Proposed Rules  

[[Page 72963]]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-311-AD]
RIN 2120-AA64


Airworthiness Directives; Learjet Model 35, 35A, 36, 36A, 55, 
55B, and 55C Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM); rescission.

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SUMMARY: This document proposes to rescind an existing airworthiness 
directive (AD), applicable to certain Learjet Model 35, 35A, 36, 36A, 
55, 55B, and 55C airplanes. That AD currently requires installation of 
a placard on the instrument panel in the cockpit to advise the 
flightcrew that the Omega navigation system may be inoperative at 
certain engine speeds. That AD also provides for an optional 
installation of certain band reject filters, which eliminates the need 
for the placard. The actions specified by that AD are intended to 
prevent excessive deviation from the intended flight path due to loss 
of navigation signals, which could result in a potentially low-fuel 
condition or a traffic conflict. Since the issuance of that AD, use of 
the Omega navigation system has been permanently discontinued; 
therefore, the original unsafe condition no longer exists.

DATES: Comments must be received by February 14, 2000.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-311-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    Information pertaining to this proposed rule may be examined at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington; or at the FAA, Small Airplane Directorate, Wichita Aircraft 
Certification Office, 1801 Airport Road, Room 100, Mid-Continent 
Airport, Wichita, Kansas.

FOR FURTHER INFORMATION CONTACT: C. Dale Bleakney, Aerospace Engineer, 
Flight Test Branch, ACE-117W, FAA, Small Airplane Directorate, Wichita 
Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-
Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4135; fax 
(316) 946-4407.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 99-NM-311-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules 
Docket No. 99-NM-311-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On September 5, 1995, the FAA issued AD 95-19-04, amendment 39-9365 
(60 FR 47265, September 12, 1995), applicable to certain Learjet Model 
35, 35A, 36, 36A, 55, 55B, and 55C airplanes. That AD requires 
installation of a placard on the instrument panel in the cockpit to 
advise the flightcrew that the Omega navigation system may be 
inoperative at certain engine speeds. That AD also provides for an 
optional installation of certain band reject filters, which eliminates 
the need for the placard. That action was prompted by reports of loss 
of certain navigation signals during extended over-water operation. The 
requirements of that AD are intended to prevent excessive deviation 
from the intended flight path due to loss of navigation signals, which 
could result in a potentially low-fuel condition or a traffic conflict.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the FAA has received notification 
that use of the Omega navigation system has been permanently 
discontinued. Therefore, the FAA finds that the original unsafe 
condition (harmonic interference from the generator, which interferes 
with Omega navigation signals and could result in loss of navigation 
signals and, potentially, a low-fuel condition or a traffic conflict) 
no longer exists.

FAA's Conclusions

    Since the unsafe condition no longer exists, the FAA has determined 
that it is necessary to rescind AD 95-19-04 in order to prevent 
operators from installing an unnecessary placard or unnecessary band 
reject filters. (Installation of certain band reject filters is 
provided in AD 95-19-04 as an optional alternative method of compliance 
with that AD.)
    This proposed action would rescind AD 95-19-04. Rescission of AD 
95-19-04 would constitute only such action, and, if followed by a final 
action, would not preclude the agency from issuing another notice in 
the future, nor would it commit the agency to any course of action in 
the future.

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Cost Impact

    The FAA estimates that 177 airplanes of U.S. registry are affected 
by AD 95-19-04. The actions that are currently required by that AD take 
approximately 1 work hour per airplane to accomplish, at an average 
labor rate of $60 per work hour. The cost of required parts (local 
manufacture of a placard) is negligible. Based on these figures, the 
cost impact of the currently required actions on U.S. operators is 
estimated to be $10,620, or $60 per airplane. However, the adoption of 
this proposed rescission would eliminate those costs.
    Should an operator elect to remove the placard required by AD 95-
19-04, it would take approximately 1 work hour per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of removal of the placard would be 
approximately $60 per airplane.
    Should an operator elect to remove the band reject filters that 
were one option for compliance with AD 95-19-04, it would take 
approximately 15 work hours per airplane to accomplish, at an average 
labor rate of $60 per work hour. Based on these figures, the cost 
impact of removing the band reject filters would be approximately $900 
per airplane.

Regulatory Impact

    The regulations proposed herein would not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) as 
follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-9365.

Learjet: Docket 99-NM-311-AD. Rescinds AD 95-19-04, Amendment 39-
9365.

    Applicability: Model 35, 35A, 36, 36A, 55, 55B, and 55C 
airplanes; equipped with Global Wulfsburg GNS 500, GNS-1000, and 
GNS-X Flight Management Systems; certificated in any category.

    Issued in Renton, Washington, on December 22, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-33734 Filed 12-28-99; 8:45 am]
BILLING CODE 4910-13-U